Prosthetic suction liners have been described in U.S. Pat. No. 4,923,474 granted to Klasson and Kristinsson on May 8, 1990; U.S. Pat. No. 5,728,168 granted Mar. 17, 1998 to Laghi et al.; and U.S. Pat. No. 5,830,237 granted to Kania Nov. 3, 1998.
The original suction liner as described in U.S. Pat. No. 4,923,474 was formed of a silicone elastomer and was adapted to the rolled over residual limb of a prosthetic user in a manner fully described in the patent.
The manufacturing process for making suction liners with a fabric exterior covering adhered to one or more cured elastomer inner layers typically involves multiple injection molding procedures and possibly laminating procedures that are designed to build-up the various layers constituting the suction liner. Obtaining an intimate bond between the silicone and fabric layers is particularly important, particularly when it is necessary to maintain full elasticity of the suction liner to enable it to closely fit over and conform to a residual limb of a prosthetic user.
The process is more complicated when a distal prosthetic connector fitting must be incorporated in the distal end of the suction liner, particularly when an injection molding procedure is utilized.
Injection molding procedures are time consuming and require complex equipment to ensure accurate shapes and thicknesses of various size suction liners. Injection molding thick, soft elastomeric layers on the inner surfaces of suction liners also present a challenge using injection molding techniques.
Prior art procedures for continuously coating tubular substrates with a cured elastomer coating or film involve many different procedures that tend to be expensive and time consuming. It is highly desirable to continuously coat tubular substrates with an elastomer layer intimately bonded or adhered to the substrate in a convenient, low cost procedure, particularly where the substrate is an elasticized, porous fabric.